Drug interactions
Protriptyline + Tolterodine
Severity: Moderate
Protriptyline and Tolterodine: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Protriptyline is a tricyclic antidepressant with strong anticholinergic activity. Combined with tolterodine it increases dry mouth, constipation, urinary retention, tachycardia and confusion. Protriptyline is also metabolized by CYP2D6 and tolterodine has QT effects, adding minor cardiac concern.
What this interaction means in plain words
Protriptyline and Tolterodine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive muscarinic receptor blockade, with possible additive QT effects.
What to do
Monitor for anticholinergic toxicity, urinary retention and heart rate, especially in older patients. Consider an alternative antidepressant if effects are troublesome.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Tolterodine
Frequently asked questions
Can I take Protriptyline with Tolterodine?
MediHelp rates the interaction as moderate. Protriptyline and Tolterodine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Protriptyline is a tricyclic antidepressant with strong anticholinergic activity. Combined with tolterodine it increases dry mouth, constipation, urinary retention, tachycardia and confusion. Protriptyline is also metabolized by CYP2D6 and tolterodine has QT effects, adding minor cardiac concern.
How serious is the interaction between Protriptyline and Tolterodine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for anticholinergic toxicity, urinary retention and heart rate, especially in older patients. Consider an alternative antidepressant if effects are troublesome.
What other medicines interact with Tolterodine?
MediHelp also lists interactions of Tolterodine with, for example, Clarithromycin, Clozapine, Cobicistat. The full list is on the Tolterodine page.
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